Welcome to Lumi

Lumi is a browser extension that helps you process videos on YouTube and Bilibili as efficiently as reading a document. This guide walks you through installation and every core feature.

Tip: Install the extension first, then follow along on a real video as you read.

Install

Adding Lumi from the store takes seconds:

Open the Chrome Web Store or Edge Add-ons page and search "Lumi".
Click "Add to browser" and confirm.
Click the puzzle icon in your toolbar to pin Lumi.

First use

After installing, open any video on YouTube or Bilibili and the Lumi panel appears to the right of the video. On first use, pick your interface and subtitle languages when prompted.

Summaries & chapters

Once a video opens, Lumi generates key takeaways and splits the content into timestamped chapters. Click any chapter to jump straight to that moment.

Bilingual subtitles

Switch to the "Subtitles" tab at the top of the panel to turn on side-by-side subtitles. Choose source and target languages — subtitles sync with the video in real time.

Transcript

The "Transcript" turns the whole video into a clean, searchable article. Skim it, copy snippets, or export in one click — ideal for notes and review.

AI video chat

Use the input at the bottom of the panel to ask anything about the video. Lumi answers using the frames and subtitles and cites the matching timestamps so you can verify sources.

FAQ

Which languages does Lumi support?

Does it work on videos without subtitles?

Where is my watch history stored?

Changelog

v1.2Transcript redesign
Cleaner layout, jump-to paragraphs, and one-click export.
v1.1Bilibili support added
Summaries, subtitles and chat now work on Bilibili.
v1.0Lumi launches
Video summaries, bilingual subtitles and AI chat go live.